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When to Plant Pawpaw in Washington County, ID

Washington County, Idaho Zone 7a May

May in the garden — Washington County, Idaho

Welcome to May in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 9
Avg. first frost October 1
Soil temp (4") 51°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Move pawpaw into the garden

    Frost risk is low now in Washington County, Idaho. If you've been covering beds overnight, you can stop.

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Pawpaw is the largest native fruit tree in North America, producing tropical-tasting custard-like fruits. Young trees prefer shade but fruiting trees need good light.

Washington County, Idaho is in USDA Zone 7a. The average last spring frost is May 9 and the first fall frost is October 1, giving you a growing season of approximately 145 days.

At an elevation of 4,048 feet, Washington County receives approximately 17.9 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Pawpaw during the growing season. With low rainfall, drip irrigation is essential for growing Pawpaw successfully. Mulch heavily to conserve soil moisture.

Washington County, ID (Zone 7a) Short season
145 days
Last Spring Frost May 9
145 growing days
First Fall Frost October 1

Washington County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 22
Recommended (50%) ✓ Fits season
Transplant: May 30
Safe Start (90%) ✓ Fits season
Transplant: Jun 28

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Washington County

How your county's soil matches Pawpaw's growing requirements.

Soil pH

Your soil pH (6.2–7.8) overlaps with Pawpaw's range (5.5–7.0), though not a perfect match.

Soil Texture

The loam soil in Washington County is excellent for Pawpaw — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Pawpaw.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Pawpaw.

How to Plant Pawpaw

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,210 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Pawpaw

Pawpaw needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Pawpaw Needs Rainfall You Supplement Action
Jan 1.1" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 4.3" 2" 2.3" 🚿 Regular watering
Jun 4.3" 1.2" 3.1" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 1.7" 2.6" 🚿 Regular watering
Sep 4.3" 1.5" 2.8" 🚿 Regular watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Pawpaw Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Pawpaw needs ~25,094 GDD — county provides 1,993 GDD May not mature

Pawpaw Planting Timeline — Washington County, ID

Pawpaw Planting Calendar

Activity When Date Range
Transplant Outdoors May 30 May 30 – Jun 13

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

1095–2555 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

145 days in Washington County

Growing Tips for Pawpaw in Washington County

Direct sow Pawpaw outdoors after May 09 in Washington County when soil has warmed and frost danger has passed.

Your 145.0-day growing season in Washington County is tight for Pawpaw (1095.0-2555.0 days to maturity). Start indoors and choose early-maturing varieties.

Washington County receives only 18" of rain annually. Pawpaw needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant at least two genetically distinct trees for cross-pollination. Provide shade for young trees. Fruits ripen in fall and have a very short shelf life. Harvest when slightly soft.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pawpaw in Washington County, ID?

Washington County is in Zone 7a with an average last frost of May 9. Plan your Pawpaw planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, ID?

Washington County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 9 and first fall frost is October 1.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Washington County, ID. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.